An inspecting apparatus of the related art has, for example, a loader chamber 1 and an inspecting chamber 2 that are adjacent to each other, as shown in FIG. 4. Loader chamber 1 has a cassette accommodating unit that accommodates a plurality of semiconductor wafers W in a cassette unit, a wafer transfer mechanism that carries in and out semiconductor wafers W one by one from the cassette, and a pre-alignment mechanism that performs a preliminary alignment of semiconductor wafers W with respect to positions thereof while semiconductor wafers W are transferred by the wafer transfer mechanism.
Inspecting chamber 2 has a placing table 3 that holds semiconductor wafer W and can move in X, Y, Z, and θ directions, a probe card 4 that is in electric contact with semiconductor wafers W on placing table 3, a clamp mechanism 5 that fixes probe card 4 using a card holder (not shown), and a coupling ring 6 that electrically contacts probe card 4 and a test head T. Further, the electrical properties of semiconductor wafers W are inspected at inspecting chamber 2 by transmitting and receiving a test signal between semiconductor wafer W and a tester (not shown) through test head T, coupling ring 6, and probe card 4 under the control of a control unit. Further, in FIG. 4, reference numeral ‘7’ represents an alignment mechanism that together with placing table 3 performs an alignment of semiconductor wafers W with probe card 4 with respect to their positions, reference numeral ‘7A’ represents an upper camera disposed on an alignment bridge, reference numeral ‘7B’ represents a lower camera on placing table 3, and reference numeral ‘8’ represents a head plate where clamp mechanism 5 is fixed.
When the electrical properties of semiconductor wafer W are inspected, a plurality of electrode pads of semiconductor wafer W and a probe 4A of probe card 4 corresponding to the electrode pads are aligned prior to the inspection, semiconductor wafer W and probe card 4 are brought into electrical contact with each other, and then the electrical properties of the device are inspected. In this process, placing table 3 is moved in the X direction and Y direction by an XY-table 9, such that semiconductor wafer W is moved to an inspection position.
Further, if necessary, it may be possible to inspect the electrical properties of a plurality of devices of a semiconductor wafer W by making all electrode pads formed on semiconductor wafer W in contact with all probes 4A of probe card 4.
However, in the inspecting apparatus of the related art, placing table 3 is widely moved in a horizontal direction by XY-table 9 in inspecting chamber 2, such that the movement area of placing table 3 becomes wider. Further, XY-table 9 is needed to be finished with high accuracy and high rigidity in order to drive and control the operation of placing table 3 in a micron-order precision, such that the weight of XY-table 9 increases. Furthermore, the diameter of semiconductor wafer W also increases, such that the weight of XY-table 9 remarkably increases.